Evaporator device with improved heat transfer and method

ABSTRACT

An evaporator device and method of making the device. The evaporator device comprises a one-piece metallic body, which is preferably aluminum or an alloy thereof, with a refrigerant tube embedded therein. The metallic body further includes horizontal fins and vertical partitions protruding from at least one surface that define an array of ice forming cells. The one-piece metallic body is formed by a die casting process that eliminates the conventional assembly steps of separate evaporator pans, refrigerant tube pieces, vertical partitions horizontal fins and other parts.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/528,227, filed on Dec. 9, 2003, the entirecontents of which are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to an evaporator device for an ice machine thathas a small number of parts and an improved thermal transfer between acirculating refrigerant and an ice-forming surface. This invention alsorelates to a method for making the evaporator device.

BACKGROUND OF THE INVENTION

Evaporator devices generally include an array of ice cells arranged in apattern and a refrigerant tube that is positioned adjacent the patternto provide cooling during ice making and heating during defrost andharvest. For example, the pattern may be a plurality of parallel rows ora grid of horizontal rows and vertical columns.

It is known to construct an ice cell array with thermally conductivemetal, such as copper or aluminum. An example of a copper evaporatordevice is shown in U.S. Pat. No. 4,459,824. The evaporator device, whenconstructed of copper, is plated with a suitable metal, such as tin ornickel. The plating is required by National Sanitation Foundation codes,which prohibit the use of copper parts in contact with food products.The plating process results in waste products that need to be handledwith environmentally acceptable procedures. In addition, platingdegradation can occur at solder fillets used in the construction of thearray of cells or their connection to other parts over which the waterused in the ice making process may flow. This can result in a formationof copper oxides that could contaminate the ice.

Examples of evaporator devices that use aluminum parts to construct theice cell array are shown in U.S. Pat. Nos. 3,430,452, 5,129,237 and5,193,357. For instance, U.S. Pat. No. 5,193,357 discloses a pluralityof horizontal integral aluminum pieces arranged side by side to form agrid of ice cells. However, the back of each ice cell contains a gapthat is filled entirely or partially with brazing material. Brazingmaterial or soldering material can deteriorate over time, therebyresulting in unreliability. Moreover, the evaporator device constructionis limited to one-sided ice cell arrays.

U.S. Pat. No. 6,247,318 discloses an evaporator device comprising aplurality of vertical partitions that are assembled side by side havingbore holes through which runs of copper tubing are threaded and thenmechanically expanded. External tube bends are then connected as bysoldering to the runs to form a contiguous winding. This evaporatordevice comprises a multiplicity of parts that must be assembled as wellas tube bends that are outside the evaporator body formed by thevertical partitions.

U.S. Pat. No. 5,129,237 discloses an evaporator device constructed of abase plate from which extend row wide fins. The evaporator device is amolded body that includes a plurality of horizontal bores that areinterconnected by a plurality of tube bends that are external to themolded body. This arrangement has the disadvantage of requiring assemblyof the tube bends to the bores of the body as well as a multiplicity ofparts.

Thus, there is a need for an evaporator device that is not formed withbrazing material or soldering material.

There is also a need for an evaporator device that has a small number ofparts.

SUMMARY OF THE INVENTION

An evaporator device of the present invention comprises a metallic bodythat has a winding pattern of a metallic refrigerant tube embeddedtherein and that is shaped to have a plurality of parallel finsprotruding from a surface thereof. The metallic body is preferably ametal that is selected from the group consisting of: aluminum andaluminum alloy.

In one embodiment of the evaporator device of the present invention, thewinding pattern is entirely embedded in the body. The winding pattern ispreferably a serpentine pattern that includes a plurality of runs thatare at least partially in registration with spaces between the fins. Therefrigerant tube has first and second ends that are located outside thebody. The refrigerant tube is preferably a metal that is selected fromthe group consisting of: copper and stainless steel.

The fins are preferably inclined downwardly at a slight angle forgravity assistance of ice removal.

In another embodiment of the evaporator device of the present invention,the metallic body comprises a plurality of vertical partitionsprotruding from the surface. The vertical partitions, the fins and thesurface define an array of ice forming cells. The winding arrangement isat least partially in registration with one or more of the ice formingcells.

In another embodiment of the evaporator device of the present invention,the metallic body has a first surface with a first plurality of finsprotruding therefrom and a second surface with a second plurality ofparallel fins protruding therefrom. The winding pattern comprises aplurality of runs that are at least partially in registration withspaces between each of the pluralities of fins.

In another embodiment of the evaporator device of the present invention,the metallic body further comprises a first plurality of verticalpartitions protruding from the first surface and a second plurality ofvertical partitions protruding from the second surface. The firstvertical partitions, the first fins and the first surface define a firstarray of ice forming cells. The second partitions, the second fins andthe second surface define a second array of ice forming cells.

A method of the present invention makes an evaporator device for an icemachine by disposing a metallic refrigerant tube having a windingpattern in a casting die and casting molten metal in the die so that themolten metal forms a body that embeds the winding pattern. The die isshaped to form a plurality of fins that protrude from a surface of thebody. The metal is preferably selected from the group consisting of:aluminum and aluminum alloy. The refrigerant tube is preferably a metalthat is selected from the group consisting of: copper and stainlesssteel.

The winding pattern is a preferably a serpentine pattern that includes aplurality of runs that are at least partially in registration withspaces between the fins.

In another embodiment of the method of the present invention, therefrigerant tube has first and second ends located outside the body.

In another embodiment of the method of the present invention, the finsare inclined downwardly at a slight angle for gravity assistance of iceremoval.

In another embodiment of the method of the present invention, aplurality of vertical partitions protrude from the surface. The verticalpartitions, the fins and the surface define an array of ice formingcells. The winding arrangement is at least partially in registrationwith one or more of the ice forming cells.

In another embodiment of the method of the present invention, themetallic body has a first surface having a first plurality of parallelfins protruding therefrom and a second surface with a second pluralityof parallel fins protruding therefrom. The winding pattern comprises aplurality of runs that are at least partially in registration withspaces between each of the pluralities of fins.

In another embodiment of the method of the present invention, a firstplurality of vertical partitions protrudes from the first surface and asecond plurality of vertical partitions protrudes from the secondsurface. The first vertical partitions, the first fins and the firstsurface define a first array of ice forming cells. The secondpartitions, the second fins and the second surface define a second arrayof ice forming cells.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, advantages and features of the presentinvention will be understood by reference to the following specificationin conjunction with the accompanying drawings, in which like referencecharacters denote like elements of structure and:

FIG. 1 is a plan view of an evaporator device of the present invention;

FIG. 2 is a side view of the evaporator device of FIG. 1;

FIG. 3 is a cross-sectional view of FIG. 1 taken along line 3; and

FIG. 4 is a view of detail 4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1-4, an evaporator device of the present inventionincludes a one-piece or integral body 22 that is a one-piece integralmetallic structure in which a refrigerant tube 36 is embedded.Refrigerant tube 36 has tube ends 38 and 40, which extend outside body22.

Body 22 has a first surface 44 and a second surface 46 that arepreferably substantially parallel and opposite one another. Body 22 alsoincludes a plurality of fins 54 that protrude outwardly from firstsurface 44. Fins 54 extend horizontally along first surface 44, arespaced from one another and are substantially parallel. Body 22 furtherincludes a plurality of fins 56 that protrude outwardly from secondsurface 46. Fins 56 extend horizontally along first surface 46, arespaced from one another and are substantially parallel. Fins 54 and 56are located substantially opposite one another.

Body 22 further includes a plurality of vertical partitions 28 disposedalong first surface 44. Vertical partitions 28 are spaced apart andparallel to one another. Vertical partitions 28 together with horizontalfins 54 form an array of ice forming cells in rows and columns.Evaporator device 20 further includes a plurality of vertical partitions32 disposed along second surface 46. Vertical partitions 32 are spacedapart and parallel to one another. Vertical partitions 32 together withhorizontal fins 56 form an array of ice forming cells in rows andcolumns.

Body 22 further includes vertical sides 24 and 26 that are substantiallyparallel to vertical partitions 28 and 32.

The ice forming cells on first surface 44 are in substantialregistration with the ice forming cells on second surface 46.Refrigerant tube 36 has a serpentine winding arrangement that has runs50 along horizontal rows of the ice forming cells. Bends 42 are arrangedwith runs 50 to form the serpentine pattern.

Each ice forming cell is substantially identical. By way of example, anice forming cell 30, which is depicted in FIGS. 1, 3 and 4, will bedescribed in detail. Fins 54A and 54B and first surface 44 of body 22and vertical partitions 28A and 28B define ice forming cell 30. Iceforming cell 30 has a mirror image ice forming cell 34 substantiallyopposite on second surface 46. The top most run 50 of refrigerant tube36 is at least partially in registration with ice forming cells 30 and34. Since refrigerant tube 36 is embedded in body 22, thermal transferfrom refrigerant flow in refrigerant tube 36 to ice forming cells 30 and34 is very efficient.

Referring to FIGS. 3 and 4, the cross-sections of fins 54 and 56 aregenerally tapered from first and second surfaces to their tips. Forexample, a surface 60 of fin 54B has a slight angle of about 30° so asto release an ice cube during a harvest cycle. A surface 62 of fin 54Bhas a slight angle of about 15° to assure that water penetrates to rearof ice forming cell 30.

In addition, the sides of the cube cells, namely vertical partitions 28and 32, are tapered outwardly from first and second surfaces 44 and 46.Preferably, the angle of taper is about 5°. This is done both tofacilitate the casting process and to let air in behind the slab of iceas it begins to slide off body 22. The angle of taper can be any anglegreater than about 1°. As the angle of taper is increased, the materialrequired for the casting increases. The smaller the angle of taper, theless impact it has on harvest because it lets less air in behind theice.

Body 22 is made by positioning the serpentine winding arrangement ofrefrigerant tube 36 in a casting die and then casting molten metal inthe die so that the molten metal encases or embeds refrigerant tube 36.The shape of the die allows refrigerant tube ends 38 and 40 to belocated outside the molten metal. The shape of the die also allowsvertical partitions 28 and 32 as well as sides 24 and 26 to be formed bythe casting process step. Thus, body 22 is formed as a one-pieceintegral structure in which the winding arrangement of refrigerant tube36 is embedded or encased.

The body 22 is preferably aluminum or aluminum alloy and refrigeranttube 36 is preferably copper or stainless steel.

All surfaces of evaporator device 20 are coated with a coating thatprevents corrosion. The coating, for example, may be nickel or tinplating.

The evaporator device of the present invention has the followingadvantages:

1. Enhanced heat transfer. Rather than heat passing through only a partof the surface of the refrigerant tube in contact with the pan holdingthe ice forming fins, the aluminum encases the refrigerant tube, therebyallowing heat transfer through the full perimeter of the refrigeranttube.

2. Enhanced heat transfer by virtue of two ice making surfaces usingonly one copper refrigerant tube.

3. Reduced part count. There is only a one-piece structure of metallicbody 22 with embedded refrigerant tube 36 vis-a-vis a traditional designthat has a refrigerant tube, a pan and a plurality of strips.

4. No reliance on sensitive bonding processes, such as soldering. Thusno chance of the evaporator assembly coming apart.

5. Lighter weight. (Aluminum vs. copper).

6. Easier to manufacture.

Although evaporator device 20 is shown with ice forming cells on bothsides of body 22, it is contemplated that body 22 may have ice formingcells on only one side. In this case, the fins of one side could beomitted or simply not used. Also, the vertical partitions can be omittedfor the case that ice cubes are not required. In such case the ice wouldbe formed along the length of the space between adjacent fins.

The present invention having been thus described with particularreference to the preferred forms thereof, it will be obvious thatvarious changes and modifications may be made therein without departingfrom the spirit and scope of the present invention as defined in theappended claims.

1. An evaporator device for an ice machine comprising a metallic body that has a winding pattern of a metallic refrigerant tube embedded therein and that is shaped to have a plurality of parallel fins protruding from a surface thereof.
 2. The evaporator device of claim 1, wherein said body is a metal that is selected from the group consisting of: aluminum and aluminum alloy.
 3. The evaporator device of claim 1, wherein said winding pattern is entirely embedded in said body, and wherein said winding pattern is a serpentine pattern that includes a plurality of runs that are at least partially in registration with spaces between said fins.
 4. The evaporator device of claim 1, wherein said refrigerant tube has first and second ends located outside said body.
 5. The evaporator device of claim 1, wherein said fins are inclined downwardly at a slight angle for gravity assistance of ice removal.
 6. The evaporator device of claim 1, wherein said refrigerant tube is a metal that is selected from the group consisting of: copper, and stainless steel.
 7. The evaporator device of claim 1, wherein said metallic body comprises a plurality of vertical partitions protruding from said surface, wherein said vertical partitions, said fins and said surface define an array of ice forming cells.
 8. The evaporator device of claim 7, wherein said winding arrangement is at least partially in registration with one or more of said ice forming cells.
 9. The evaporator device of claim 1, wherein said surface is a first surface, wherein said plurality of fins is a first plurality of fins, and wherein said body is shaped to have a second surface with a second plurality of parallel fins protruding therefrom.
 10. The evaporator device of claim 9, wherein said winding pattern comprises a plurality of runs that are at least partially in registration with spaces between each of said pluralities of fins.
 11. The evaporator device of claim 9, wherein said metallic body further comprises a first plurality of vertical partitions protruding from said first surface and a second plurality of vertical partitions protruding from said second surface, wherein said first vertical partitions, said first fins and said first surface define a first array of ice forming cells, and wherein said second partitions, said second fins and said second surface define a second array of ice forming cells.
 12. A method of making an evaporator device for an ice machine comprising: disposing a metallic refrigerant tube having a winding pattern in a casting die; and casting molten metal in said die so that said molten metal forms a body that embeds said winding pattern, wherein said die is shaped to form a plurality of fins that protrude from a surface of said body.
 13. The method of claim 12, wherein said metal is selected from the group consisting of: aluminum and aluminum alloy.
 14. The method of claim 12, wherein said winding pattern is a serpentine pattern that includes a plurality of runs that are at least partially in registration with spaces between said fins.
 15. The method of claim 12, wherein said refrigerant tube has first and second ends located outside said body.
 16. The method of claim 12, wherein said fins are inclined downwardly at a slight angle for gravity assistance of ice removal.
 17. The method of claim 12, wherein said refrigerant tube is a metal that is selected from the group consisting of: copper and stainless steel.
 18. The method of claim 12, further comprising a plurality of vertical partitions protruding from said surface, wherein said vertical partitions, said fins and said surface define an array of ice forming cells.
 19. The method of claim 18, wherein said winding arrangement is at least partially in registration with one or more of said ice forming cells.
 20. The method of claim 12, wherein said surface is a first surface, wherein said plurality of fins is a first plurality of fins, and wherein said body is shaped to have a second surface with a second plurality of parallel fins protruding therefrom.
 21. The method of claim 20, wherein said winding pattern comprises a plurality of runs that are at least partially in registration with spaces between each of said pluralities of fins.
 22. The method of claim 20, further comprising a first plurality of vertical partitions protruding from said first surface and a second plurality of vertical partitions protruding from said second surface, wherein said first vertical partitions, said first fins and said first surface define a first array of ice forming cells, and wherein said second partitions, said second fins and said second surface define a second array of ice forming cells. 